The field of the invention is manufacturing semiconductor wafers and similar articles.
Semiconductor devices are used in a wide range of consumer electronics, computers, communication equipment, and various other products. Semiconductor devices are generally made from wafers of silicon, or other semiconductor materials. The wafers are processed through many manufacturing steps, to form microelectronic circuits. During various steps in manufacturing, the wafers are processed using fluid chemicals (e.g., acids, caustics, etchants, photoresists, plating solutions, etc.). They are also rinsed and dried, to remove contaminants which can cause defects in the end product devices or interfere with subsequent process steps. However, the processing or rinsing fluids themselves have potential for unintentionally depositing a residue or particulate contaminants on the wafer, if fluid dries on the wafer surface. Thus, fluid is preferably removed quickly and completely from the wafer.
Deionized (xe2x80x9cDIxe2x80x9d) water is frequently used as a rinsing fluid. DI water, as well as other fluids used in manufacturing semiconductors, will cling to wafer surfaces in sheets or droplets, due to surface tension. Consequently, the surface tension forces must be overcome to remove the sheets or droplets, and to thereby leave no fluid-borne contaminants on the wafer surfaces.
Various approaches have been used in the past to reduce the level of contaminants left on the wafer surface after processing or rinsing and drying. These include spin rinser machines, alcohol vapor machines, as well as equipment using combinations of spin, alcohol, and heat. While several of these approaches have performed well, there is a need for improved processing and drying methods and equipment.
In a first aspect of the invention, a method for processing a semiconductor article includes the steps of withdrawing the article from a processing fluid at an inclined angle. The article is withdrawn at a selected withdrawal rate. The article is advantageously exposed to a vapor of an organic solvent. After the wafer is completely withdrawn from the fluid, the wafer is spun momentarily, via a rotor, to centrifugally remove any fluid remaining on the wafer.
In a second aspect of the invention, a dry gas, such as nitrogen, is mixed with the vapor.
In a third aspect of the invention, the spin time of the wafer is limited, to avoid drying fluid on the wafer.
In a fourth aspect of the invention, an apparatus for drying a semiconductor article, such as a wafer, includes a lid attached to a body. A basin in the body holds a rinsing liquid. A rotor within the body, above the basin, has a spin motor for spinning a wafer. An elevator attached to the rotor moves the rotor vertically, to immerse and withdraw a wafer from the rinsing liquid. A pivot motor in the elevator pivots the rotor into a face up position, for loading and unloading a wafer, and into a downwardly inclined position, so that the wafer is withdrawn from the liquid at an inclined angle.